Murder on the Hogwarts Express
by violet lily13
Summary: When a Slytherin prefect is found dead on the way to Hogwarts, mystery lover Nymphadora Tonks takes the case to find the killer. But on the way, she discovers that being a detective can be more deadly than being the victim... complete!
1. A Ghastly Discovery

**Murder on the Hogwarts Express **

_Author's Note:_ the characters of Tonks and the Weasley brothers, as well as the magical world they come from, is all the intellectual property of J.K. Rowling. The book _Murder on the Orient Express_, from which the idea of this story was taken, is the property of Dame Agatha Christie. Also, a special thanks to timeturner, MadameSnape, and the rest of the people at HPFF who gave their support and contributed ideas.

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The clock struck nine as Nymphadora Tonks, who preferred to be called by her surname, burst through the barrier to Platform 9 ¾ of King's Cross station. She cursed silently at her trunk, which was too heavy for her to lift onto the train before it left. The porter took it from her, effortlessly adding it to the baggage car. 

"You better hurry up, miss," he told her. "The train's about to leave."

Tonks ran to the first carriage and jumped on just as the engine began to roll forward in a huge burst of steam. She slowly walked up the aisle, looking for an empty compartment, or at least one with someone she knew. It seemed as though every compartment she passed was full of rowdy first years or serious-looking fifth and seventh years who didn't look too happy about having to write their OWLs and NEWTs this year. Tonks smiled to herself, at least she had another year until she had to worry about that.

Finally, as she neared the front of the train, she found a suitable place for her to sit. The compartment was nearly empty except for two teenage boys with bright red hair. The younger of the two was covered in freckles, so much so that he seemed to have darker skin than he really did. Tonks grinned as she watched him drawing pictures of dragons on a slim notebook.

_If there was one thing Charlie Weasley likes_, she thought to herself. _It's dragons._

Across from him sat an older boy who looked quite different, though it was easy to tell that he was Charlie's brother. His red hair was far longer and his build was slim and tall rather than stocky like Charlie. It would be Bill Weasley's final year at Hogwarts and it was rumoured that Gringotts bank was after him to become a curse-breaker. At the moment, however, he was scratching his chin with a quill and scribbling notes on a spare piece of parchment.

Tonks struggled to open the compartment door and stumbled in. The two brothers looked up; Bill merely rolled his eyes and went back to his parchment while Charlie tried to hide a laugh behind his hand.

"Always got to make an entrance, don't you?" he asked.

Falling into the seat beside him, Tonks stuck out her tongue. "Least I made it on time. It was close, I'll tell you."

Bill, with his Head Boy badge shining in the late summer sun, nodded towards her hair. "Nice colour. It matches your tongue perfectly. I'm sure your mum was happy about that."

Tonks reached a hand towards her short, bubble-gum pink hair.

"She wasn't happy, not that it matters at all," she replied. "It's not permanent or anything. Here, watch this."

Screwing up her face, Tonks' hair turned a rather ghastly shade of lime green.

"Is that any better?"

Charlie finally was unable to resist the urge to laugh out loud. "Rather looks like one of my dragons," he said, holding up the sketchbook.

Bill muttered something about immaturity and stood, carefully tucking the parchment into his robes. Before he left the compartment, he turned back to the younger witch and wizard.

"Now, I'll be off doing my rounds and I don't want to hear anything about you two getting into mischief," he declared, his voice serious. "That episode last year did nothing to help either of your reputations -"

"Oy," Tonks interrupted. "It wasn't our fault that Snape walked into the girl's lavatory and..."

"But you admit that you had something to do with it," Bill shot back.

"At least we're not as bad as the twins," Charlie, ever the peacemaker, commented.

Bill sighed, obviously thinking about his troublesome younger brothers.

"Thank Merlin they're not at school yet. I won't have to deal with the likes of them while trying to maintain some sanity as Head Boy. But please," he added, his voice slightly desperate. "Don't do anything you'll regret."

"Of course we won't," Tonks promised, taking a small yellowback book from her jacket pocket (as she had not yet changed into her robes, having only boarded the train a few moments before). "I'll be reading while Charlie draws his pictures. How much trouble could we possibly get into doing that?"

Bill looked as though he were about to say something in reply, but he merely shook his head and left the compartment, quietly shutting the door behind him.

Tonks slouched in her seat, trying to find a nice position for reading. At home, she was never allowed to sit like that as her mother always insisted that it was unhealthy and unladylike. But here, with no mother around to bother her, Tonks was quite comfortable sitting any way she liked. Opening the book, she turned to the first chapter and began reading.

"What is that book?" Charlie asked suddenly. "It can't be a schoolbook, not with you."

"It's a murder mystery," she replied, loudly chewing a wad of gum she'd stowed in her pocket before leaving for the station. "My dad likes reading them and I got hooked, though mum doesn't approve. She says they're too gruesome, but I tell her that being an Auror won't be any cleaner or safer."

He looked perplexed. "What are they, exactly?"

"It's when a person gets murdered and a detective comes along and solves who did it. They're really quite fun to read, you know, trying to guess who the murderer is." She held up the book to show him the cover picture, which showed the body of a man lying on a floor with a knife sticking out of his chest. "This one's about my favourite of them all. It's called _Murder on the Orient Express_ and got a horrible person who's found dead on a train with a dozen stab wounds in him. The little detective guy goes along and finds out the most brilliant solution, which, of course, I won't tell you because that'd give it away. It's quite ingenious, really."

The expression on Charlie's face was a mix of disgust and curiosity. "Merlin, those muggles write about strange things," he said, shaking his head. "You'd never see anything like that in Flourish and Blotts."

"Ah, you wizards are missing out on the best of literature," Tonks replied with a wink.

She went back to her book and he to his drawings. Nearly a quarter of an hour ticked past as the two of them quietly kept to themselves while the sounds of the rest of the students leaked through the compartment door. During that time, the trolley witch passed by and asked them if they wanted any candy. Surprisingly for her, they declined her offer.

Tonks was just coming to the part when the body was discovered when a bloodcurdling scream rang out through the train. Both she and Charlie leapt from their seats and ran out the door to see where the screams were issuing from. The compartment next to them, closest to the front of the train, had its door open. Standing there was one of the prefects, a girl from Hufflepuff, her voice seemingly hitting the highest notes of the scale with her loud cries.

"Bloody hell, what's the matter?" Tonks asked, trying to calm the girl down.

Unable to speak, the girl pointed to something inside the compartment, her hand shaking. Tonks left the girl and looked into the compartment, usually the place where the prefects met before going on their rounds of the train.

Its only occupant at the moment was a body lying on the floor in a pool of blood, a knife visibly sticking out of the stomach, just like the cover of Tonk's book.

"What is it?" Charlie asked from behind her.

Tonks turned, her face a ghostly shade of white. "A very dead body. We're in serious trouble, Char. Just wait until your brother hears of this."


	2. On the Case

_Note: the disclaimer is the same as before. The names of OC's might be of interest, however, as they are created from the names of characters from various mystery novels and shows.

* * *

_

**Two****  
**

Tonks slowly moved over to the body, feeling as though she had just stepped into a book and become one of its characters. She knelt down beside it and gently placed her hand on the boy's neck. No pulse flickered beneath her fingers; he was definitely dead. Balancing on the balls of her feet, Tonks took a long look at the body, trying to remember every detail she could.

He had golden blond hair and lily white skin with an almost-feminine aspect to it. There were no blemishes or bruises whatsoever on his visible parts, except, of course, for the knife. His robes were new, Tonks noticed from the way that there were barely any signs of wear upon them. The symbol of Slytherin house decorated the front of his robes, as did the prefect's badge that now had a small splattering of blood upon it.

"What was his name?" Tonks asked the Hufflepuff girl, who was now crying on Charlie's shoulder as other students began gathering around to see what had happened.

The girl sniffed loudly and looked up, having wiped off most of her mascara on Charlie's robes. "Gilbert Moriarty."

"Can you tell me what happened, - ?" Tonks broke off, not knowing the girl's name.

"It's Ariadne Vane," the girl replied, taking a lace-edged handkerchief from the pocket of her robes. She swallowed, then continued. "We had been sitting here together after the other prefects had left. We were to take the later turn at rounds of the train. Gil and I were talking about how different school was going to be this year now that we're prefects. Then I got up to change into my robes." She stopped for a moment and bit her lip. "He said he'd change later, he had to do something first."

"Do you know what it was he had to do, Ariadne?" Tonks asked.

The girl shook her head. "Sorry, I have no idea." She looked back at the body and the tears began running down her face once more.

"Charlie, can you find her friends for her or something?" Tonks suggested, feeling sympathy for the girl, who obviously had seen nothing like a dead body before. "She seems quite broken up about this."

He nodded and led her off, leaving Tonks to look back at the body. Other students were beginning to gather around the compartment door, asking her questions, but she ignored them, trying to catch every piece of evidence before any of the other prefects arrived.

She reached into the pocket of her jacket and took out the tissues her mum had stored there, _just in case you get a runny nose, dear_. Tonks wrapped her one hand some of the tissues and slowly reached for the knife sticking from the boy's chest. She had to get a good look at the murder weapon without destroying any fingerprints on the knife itself. Just as her hand, covered in the tissues, was encircling the knife, a pair of familiar shoes appeared in her line of vision.

"What do you think you are doing, Nymphadora?" Bill Wealsey asked.

Tonks glared at him. "I am collecting evidence, if you don't mind."

"Actually, I do mind," he remarked. "In case you've forgotten, I am Head Boy."

"Yeah, I remember that fact. The only problem is that unless you can provide a good alibi, you're on the list of suspects."

While he spluttered in shock, she took a deep breath and yanked the knife from Gilbert Moriarty's chest. The strange noise it made caused her to shudder with distaste, but she quickly recovered and placed the knife on the rest of her tissues.

"So you think I did it? What in Merlin's name - " Bill began, his voice rising.

She rolled her eyes dramatically. "I didn't say _that_, Bill. A detective has to be careful in who they trust, you know. And the only one I can trust right now is Charlie 'cause he was with me when it happened. Even the trolley witch is under suspicion."

"So you're a detective now, are you?" he asked incredulously.

Tonks leaned over the body and stared at the wound, a pained expression on her face.

"Indeed I am. Do you happen to have a pair of tweezers on you?"

Before he could answer, she dug once more in her pocket and produced her wand along with the stub of a pencil.

"Never mind," she said, raised her wand over the pencil. "I can make my own. Professor McGonagall'd be pleased with me using _something_ she taught."

"Tonks, maybe it'd be better if - " Bill started to say, but was cut off by the small cloud of smoke that suddenly surrounded his brother's friend. He heard her coughing slightly, then an arm poked out of the smoke.

"Ha!" she exclaimed. "I _can_ Transfigure things!"

"There was never any doubt of that," Charlie said, entering the compartment. He turned to his elder brother. "What should we do about all those people outside, Bill? They're getting downright impudent, if you ask me, wanting to see the body and all."

Bill hesitated for a moment, as though he were thinking deeply about something, then he nodded his head. "Since you are such a great detective, my dear Nymphadora, I'm leaving you in charge of the body until we arrive at Hogwarts. If you can, and only if you can, find out who did this. Understand?"

Tonks pursed her lips and nodded solemnly. "I'll find the murderer, Bill, don't you worry."

"That's exactly what worries me," he responded, then left the compartment. His voice could be heard soon after telling the students to go back to their seats, that everything was under control.

Which, according to Tonks, it was.

She took her newly-made tweezers and leant over the body once more, her eyes squinted as though she were looking for something very small. Carefully keeping her hand steady, she picked up what seemed to be a hair and turned to show it to Charlie.

"Look at this," she said to him. "It must have fallen off the killer."

"Or it could just be a hair from his mother or girlfriend," he pointed out in reply. "You know, Tonks, it's impossible to say whose it is or where it came from without all those gadgets like Dumbledore has in his office."

Tonks held the hair up to the light and stared at it, almost willing it to give up its secrets.

"It's of a thick texture and brownish-looking, I would say," she said. "Though it's hard to tell whether it's from a girl or boy, it's of the length that could be either."

Charlie stood there, feeling a mix of impatience and ignorance in just standing there while Tonks did all the work.

"Is there anything you need me to do?" he asked, his voice cracking somewhat at the end. He was not used to seeing dead bodies of fellow students with knives sticking out of them.

Tonks looked up from her examination of the hair. "Yeah, there are a couple of things I need done. You still got your sketchbook with you?" He nodded. "Good, you'll need it to take notes when you're talking to possible witnesses in the surrounding compartments. Check to see who was about and whether anyone heard or saw anything before Miss Oh-So-Pretty-Prefect began screaming to no tomorrow."

Charlie raised an eyebrow at his friend's change of tone. She sounded more like an hard-boiled American than a Scotland Yard detective.

"And," she continued, oblivious to his facial expression. "I'll also need some powder and a make-up brush. I'm sure that one of the girls on board will have one with them."

This last was just too much for Charlie. "What do you need that for? Surely not for yourself or for him," he said in consternation, pointing at the body.

She sighed patiently and looked straight at him, her dark eyes strangely serious. "For fingerprints, of course. I'll dust the knife, then compare any prints on it to people on the train who might have killed him. Most likely it's the only way we'll find who did it before we get to the school."

His gaze fell from hers and travelled over to the bloody knife that lay on the pile of tissues.

"Right then," he said, trying to keep his voice straight. There was a murderer on the train and they had no idea who. _What could that person do next?_ he wondered. "I'll get on that, Tonks."

She grinned suddenly, her eyes once more taking on that signature twinkle of hers.

"That's Inspector Tonks to you, laddie. And don't forget it."

With a short laugh, Charlie left the compartment to set out on his task, leaving Tonks to sort out the physical evidence of the body and anything else she found in that compartment.


	3. Friends or Foes?

Disclaimer: the world and most of the characters involved in this story are the property of J.K. Rowling.

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**Three**

Once Charlie had gone, Tonks leaned over the body once more, this time looking more closely at the face. It's unearthly calm bothered her greatly._ How could anyone who was being stabbed seem so calm in death? _she wondered. Then she smelt the horrid stench coming from the prefect's mouth.

Swallowing the bile that had rushed up her throat, Tonks backed away from the body, coughing. No one's breath, not even Professor Snape's, smelt that bad. Obviously, something other than simply a stabbing had occurred.

An idea suddenly popped into Tonks' head. She ducked to look _under_ the seats. If it was as she thought... There, under the seat closest to the window, was a small glass vial, like the sort that was used in upper year Potions classes. Pulling another of her mother's tissues from her pocket, Tonks gently picked up the vial and sniffed it. Her head began to swim and her eyelids became heavy before she shook herself out of a near-stupor.

_Now that's a strong sleeping potion_, she thought, holding the vial away.

There were plenty of strange things in the compartment for her to find. She quickly went to work to find them all before they arrived at Hogwarts. The least she could do was gather all of the evidence for the authorities and present it to them upon arrival. If Bill had done anything, it was alert Professor Dumbledore of the murder and he would in turn tell the Aurors, who would most likely be waiting at Hogsmeade for the train.

Charlie, meanwhile, was not having an easy time with the students in the rest of the train carriage. While some were as closed-mouthed as clams, others spouted off nonsense about shadowed figures and mysterious noises. Charlie wished he had been given a simpler task, or at least one that did not have to do with interrogating uncooperative people.

"Did you see or hear _anything_ unusual around 9:30?" he asked for what seemed the millionth time. "Any shouts, yells, crashes..."

The second year he was interviewing looked up at him with wide blue eyes and shook her head very slowly, not taking her eyes off of Charlie's face. Feeling dejected, he thanked the girl and left the compartment.

_Were all these people both blind and deaf?_ he asked himself. _Or did they just not care?_

He knocked on the door to the next compartment, not expecting anything to come of this interview. The voice that answered his query was gruff, but affirmative. Charlie entered to find only one inhabitant, a tall Ravenclaw boy who looked to be in his seventh year, with the hint of a beard growing on the dark skin of his cheeks.

"You 'ere about the problem up in the prefect's compartment?" the boy asked with a thick accent that Charlie couldn't place.

"Yes," Charlie replied, suddenly feeling nervous. He had a feeling that this boy knew something, Charlie could see it in his eyes. "I was just wanting to know if you saw or heard anything suspicious before the girl's scream."

"Aye, I saw your brother go by, lookin' like he was in deep thought," the older boy replied. "But I don't suppose you're thinkin' that 'e did it?" Charlie shook his head. "Nah, didn't think so. Well, there was also someone else walkin' by, but I didn't get to see 'oo it was."

Charlie blinked, trying to translate the other boy's words. "Really? Can you describe them at all for me?"

"Well then, let me think a bit," the boy said, screwing up his pliable face in thought. "They was not too tall, per'aps a small person from the lightness of their footsteps, but you never know, they could've been sneakin' 'bout the place."

Leaning forward with anticipation, Charlie asked, "Did you see anything? The colour of their robes or hair...?" He left the question hanging.

After a moment's hesitation, the boy replied. "Aye, they be wearin' black and 'ad dark 'air. Not like yours at all, mate."

Charlie sat back, trying not to show his disappointment. Probably half the people on the train had dark hair, and everyone who'd already changed into their robes would be wearing black.

"Thanks," he managed to say, closing his notebook and rising from his seat. "If we need anything more from you - "

"I'll be 'ere," the boy interrupted with a grin. "Don't you worry."

In the next compartment, Charlie fared a little better. The occupants, a group of Slytherins who had personally known Gilbert Moriarty, were not willing to tell Charlie a bit about the personality of their old housemate at first.

"Why should we be telling you anything?" a hard-faced seventh year asked. "What makes you think that we should talk to a Gryffindor about all this?"

Charlie bit his lip, knowing that Tonks would easily retort that it was the right and just thing to do. But Charlie did not have Tonks' quick wit or tongue.

"We have to find who did it because..." he began, trying to keep his voice from cracking. Then an idea hit him. "Because we don't know if they'll strike again. You never know, with these murderers."

"Are you saying that they might come after us?" a dark-haired girl squeaked in fear.

Charlie nodded sombrely, playing into the role. "Yes, I do. Please tell me all you know about Gilbert Moriarty. To know all about his character might lead to the villain before anything else...happens."

If there was one difference between Slytherins and Gryffindors, especially in this time of peace, was that, although ambitious and ruthless, Slytherins were only out to save themselves. Bravery or courage simply did not figure into the equation. As soon as Charlie Weasley had uttered those words, the group of Slytherins shuddered and glanced at each other suspiciously, as though they thought the murderer in the room with them (which, Charlie noted, was indeed possible. All at once, they began to speak.

"Right old bastard he was," a fifth year boy was saying. "Thought himself better than the rest of us, just because he was now a prefect and we weren't. He wasn't my friend, I'll tell you that much. He was too arrogant even for the likes of me!"

"Moriarty was worse than Snape and McGonagall put together," a fourth year girl complained. "I've never met anyone so bossy in my life. It was always 'do this' or 'do that' from him, never a word otherwise. Like he knew the rules and we didn't. He used to be bearable, but oh my gosh, over the past year he was the last person I'd want to spend a moment with."

"I just feel sorry for his dorm mates," the dark-haired girl piped up. "At least the rest of us could get away from him sometimes."

"Was he very smart?" Charlie asked, cutting into the ruckus.

"Definitely," a blond fourth year boy replied. "Smart as a Ravenclaw he was. Knew all the answers all the time, and he let everyone know it. Was hoping for all O's on his OWLS in the spring. Personally, I think that he would've got them, too."

"Wouldn't let anyone get ahead of him either," a fifth year girl added. "Anytime that someone would beat him at something, he'd be right beastly to them for days. Thought he was the pick of the crop, he did."

"Did he have any real enemies? Like, people who would kill to be rid of him?" Charlie wondered aloud, leading the Slytherins on in their unpleasant eulogy of the dead boy.

"Not really," a small, dark boy said pedantically. "No one liked him, but no one hated him either. Lots of the younger students looked up to him as a bit on an idol. The rest of us bore his bossy arrogance. He was a pain, but not a bad chap."

"He was nasty, but not horrible," the blond boy agreed hesitantly. "I can't think of anyone who would have hated him that much. Like, he could say some rotten things at times, and that could make someone want to...want to kill him, I suppose."

All of a sudden, the compartment went quiet. The Slytherins avoided each others' gazes, looking at the floor, the ceiling, or out the window, but not at each other. Charlie realized that it had finally hit them that Gilbert wasn't coming back; he was gone forever. Closing his notebook, Charlie quietly left the compartment, leaving them to their silent mourning.

As he travelled back up the carriage to where the body was, he saw Tonks coming towards him, a look of shock and what seemed to be fear on her face.

"Charlie, we have a big problem," she said, her voice hushed so that no one else could hear. "I think I know what happened and it's not at all good."


	4. The Science of Deduction

_Disclaimer: _the characters and setting belong to J. K. Rowling. The mention of Peter Wimsey and the quote from him are the property of Dorothy L. Sayers.

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**Four**

Charlie was astounded. He had left Tonks barely half and hour before and she had already solved the case without his help. How was that possible? He told her so and she laughed, patting his arm comfortingly.

"Oh come on, Charlie!" she said, amusement filling her eyes. "Do you really think I could do it that fast? I only told you that I knew _what_ happened, but not _who _did it."

He frowned, trying to understand her logic. "So you know how he died, but you still don't know who killed him?"

"Elementary, my dear Watson," she acknowledged with a mock bow. "As the great Peter Wimsey said, 'Once you know how, you know who'."

"I'm not even going to ask who or what you're talking about," Charlie said, crossing his arms. "Do you want me to tell you what I know, or do you want to go first?"

"You go first, Char," she said, turning back towards the compartment where the body still lay. "Maybe what you've heard from the others on the train will help us figure out who may of done the crime."

So he told her all he had heard, mostly concentrating on what the Ravenclaw boy and the group of Slytherins had told him. Tonks found the mixed views of Gilbert Moriarty very intriguing, especially since the Hufflepuff prefect had claimed that he had been personable to her_. Why would a Slytherin who couldn't even get along with his own housemates have a deep conversation with a Hufflepuff, of all people? _ She decided to let the question go for the time being. The two of them would interrogate the prefects later on. Hopefully, then they would find the answers they needed to solve this crime.

The two of them were standing outside of the compartment containing the body as Charlie finished his report. Tonks suddenly felt apprehensive about her own news, which was not at all pleasant. It frightened her greatly to think about the cold-hearted planning that had gone into carrying out this villainous deed.

"Charlie," she whispered, leaning forward so that only he would be able to hear her. "I don't like this one bit. The things I discovered after you left..."

His brown eyes opened wide. "What, what was it? It must be pretty bad if it's bothering you like this, Tonks."

"It is," she replied, her voice catching slightly. She slid open the compartment door and the two of them slipped in. "This is worse than I previously thought. It was not a random act, or one that happened in the heat of the moment. This was premeditated, planned out beforehand."

"But how - ?" he asked, surprise evident in both his face and voice.

"Remember how it seemed strange that he'd let himself get stabbed without crying out?" Tonks explained, her voice low. "Well, he was asleep at the time. I don't even think he woke up when the knife entered his stomach." She held up the small glass vial she had found earlier. "Sleeping drought, and a very strong one, too. Very few would be able to produce one quite like this, only upper year students."

"So someone slipped him that in a drink, you're thinking?"

"It's very possible, unless of course he took this because of motion-sickness. He was a Slytherin after all, and a smart one at that. He could've easily made it himself and taken it."

"Then whoever killed him had to have known that he had taken it," Charlie pointed out. "Either that or they're the one's who gave it to him."

"So it would have to be someone who knew him well enough or someone he trusted," Tonks deduced, her usually smooth forehead deeply furled. "That narrows it down a bit."

"But from what I heard, not too many people thought the world of him," Charlie said. "Nor did he think much of anyone else."

A small, but bitter, smile appeared on her face. "One thing you'll have to learn in detecting, Charlie, is that no one can be trusted. We can't be sure that any of the witnesses are telling the truth. In fact, we have to look at the case from two ways," she began pacing the small space to one side of the body. "One way is to use what all the witnesses say and see what you get from all that. The other way is to use the concrete evidence and see what that tells us about the dirty deed. It's all elementary, really."

Charlie looked more than slightly perplexed. "Sometimes, Tonks, I really worry about you."

"Why?" she asked, looking up quizzically.

Unable to think of anything reasonable to reply with, he decided to change the subject. "Did you find anything else while I was gone?"

Tonks stopped in mid-step and pointed to the bloody knife which lay on the ground nearby. It was still partially wrapped in tissues, but there was something strange about it that Charlie had not noticed before.

He carefully stepped over the body and knelt down to get a closer look at the knife. The blade was a hand's breadth in length and, where there was no blood, made of shiny steel. On the other hand, the hilt looked like a very old ebony, inlaid with mother-of-pearl. It looked well-made and very expensive.

"Why would they use a knife, Tonks?" he asked, frowning over the object. "We're all wizards or witches here, surely if we wanted to kill anyone it'd be easiest to use magic."

Tonks sat down in the seat closest to the window, leaning her head against the wall.

"I was thinking that same thing earlier," she said, her eyes closed. "But then I remembered something my mom said about magic being traceable, that the Ministry can figure out who used a certain spell by something to do with the wand. Perhaps that was the reason here."

"But a knife is just as traceable, isn't it?"

"Unless it was stolen, of course."

"A wand can be stolen as well, don't forget," Charlie remarked.

Her eyes flew open and she grinned. "Touché. But we're still left with the problem of finding out who did this." She motioned to the body lying on the floor. "I still have to look for fingerprints on the knife and the vial, though. That could help us a bit."

Charlie looked closely at the wooden handle, his eyes squinting. "I don't know much of anything about fingerprints, but do you think that this is one?" He pointed at a smudge where the hilt met the blade.

Tonks quickly crossed the space and knelt beside Charlie.

"It could be," she admitted. "But it's hard to tell without the proper equipment. Do you know anyone with a white powder of some sort? Girl's make-up might do the trick. I think I asked you to get that before."

"No one I talked to had any that they were willing to lend out," he said, his cheeks flushing. "Maybe one of the prefects will have what you need."

Tonks sighed impatiently. "Oh well, I suppose so. We'll also have to compare that hair I found earlier with someone on the train." She paused for a moment, rubbing her chin with one hand. "Tell me, what colour was that Ravenclaw boy's hair?"

Charlie thought for a moment, remembering. "It was a sort of brownish colour." Then he seemed to realize what she was getting at. "You don't think - "

"As I said, you can never trust witnesses, however much you want to do so," she interrupted, standing and brushing imaginary dust from her clothes. "We still have a couple of hours before we arrive at Hogwarts, but we've got a lot to do." She went back to pacing the compartment, waving her hands wildly as she spoke. "First of all, we'll talk to the prefects. Bill has got a watch on them already, so hopefully they'll all be in the same place. We have to talk to them one by one, though, so they can't hear each other's stories and collaborate on them. We need the truth!"

At this statement, she banged her fist against the other hand, making Charlie jump.

"What then?" he asked.

"We'll check this compartment for fingerprints once we have the proper stuff to do it with, then we'll go on and interview more people." Her eyes took on a strange glow. "The trolley lady will have to be questioned thoroughly, who knows what she may have seen and remember how she offered us food right before that girl began screaming. She could have easily drugged Moriarty and killed him."

"Why would she do that?" Charlie inquired, his mind whirling with all she was telling him.

Tonks spun to face him. "Why not? Motives can be aplenty when the victim is not liked very much, as seems to be the case with him." She pointed at the dead boy, still wide eyed with the shock of death. No one had thought to cover him yet.

"But who will watch over the body when we're gone? We can't just leave it here!"

A sudden look of confusion appeared on Tonks' face. Her eyes moved from the body, to the door, and back again. "Oh dear. I never quite thought of that. We can trust your brother Percy to sit with it, cant' we?"

"He's only a first year!" Charlie exclaimed. "I can just see the look on mother's face if she heard that her dear little Percy was exposed to a dead body on his first day!"

"Bad idea, right," Tonks said, biting her lip. "What about a porter?"

Charlie stood up. "I'll get one." He left the compartment hurriedly.

Tonks sat in one of the seats and gazed at the boy's lifeless body for a few moments. Then a mischievous smile spread across her face as she reached into her jacket pocket and pulled out a scrunched brown hat. Shaking it to get rid of some of the larger wrinkles, it became apparent to the type of hat she was holding.

Placing it on her head with a flourish, she said to herself, "The game's afoot."


	5. The Prefects Part One

Disclaimer: same as before

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**Five**

Tonks knocked on the door to the compartment before entering. Behind her, Charlie was turning to a fresh page in his notebook and making sure that his charcoal pencil was sharp. Both of them kept their faces grim, not wanting to reveal any weakness to the older and more powerful students they were about to interview. The seven remaining prefects of Hogwarts were upstanding students hand-chosen by the Headmaster to patrol the halls and keep peace among the throng of younger students. A throng that incidentally included both Tonks and Charlie.

The feelings of anxiety radiating off of the seven prefects inside was enough to bring perspiration to Tonks' temples. In spite of herself, she was feeling nervous about interviewing these students. It was possible that any one of them could be the murderer, but at the same time, each of them could have been in danger of their lives if the killer chose to strike again.

Bill was there, standing by the window, his face passive, but somewhat strained.

"Prefects," he announced. "This is Nymphadora Tonks and my younger brother, Charlie. I've given them permission to look into this ... sensitive manner. They'll be asking you some questions about Mr. Moriarty, one at a time. Who would like to go first?"

Tonks stepped forward. "Bill, if it's alright, could we start with the other Slytherin prefect?"

The Head Boy glanced over at a painfully thin girl with extremely pale skin and hair so black it had a blueish sheen to it. She stood up, her robes baggy over her thin frame.

"Of course I'll go," she purred in a husky voice. "Anything to help you out." She smiled, but it did not reach her crystal-like grey eyes. She held her hand out to the two fourth-years. "I'm Harriet Adler, nice to meet you."

Tonks stared at the girl while Charlie delicately shook Harriet's hand as though he was afraid it might shatter in his grasp.

"The next compartment over is empty," Bill told them. "You can hold your interrogations there." His voice was slightly sarcastic with this last statement, and Tonks barely refrained from sticking her tongue out at him.

The three of them - Tonks, Charlie, and Harriet - moved over to the next compartment over, where Tonks immediately filled all corners of the space with a silencing charm. She did not want anything to be heard by an eavesdropper. Turning to the other two, she sat down on one bench and nodded to have Harriet sit across from her. Charlie sat by the window, watching the two girls with worry written across his face.

"Now, Miss Adler," Tonks said, her voice deadly serious. "Some of these questions I have to ask you could be personal, or at worst, disturbing. Please forgive me if I offend you."

Harriet nodded, her face set like a porcelain mask.

"First of all, how well did you know Gilbert?" Tonks asked, her voice emotionless.

Letting out of breath of what seemed to be relief, Harriet sat back in the seat. "As well as can be, seeing that we were in the same year. He wasn't the talkative sort, you see."

Tonks snuck a look at Charlie, who was writing down every word the two girls said.

"From what you knew of him," she continued. "What did you think of him?"

Harriet smiled condescendingly. "It's not polite to speak ill of the dead."

"Tell us anyway," Tonks shot back, her dark eyes burning like coals. "This is an investigation, Miss Adler. It would be most ... helpful of you to tell us everything you know. The truth would be a bonus," she added with the slightest tone of sarcasm.

Harriet's face changed for a fraction of a second, her eyes sharpening and her mouth turning into a sneer. It was gone in a blink and she became a statue once again.

"Gilbert was a snob," she replied. "He thought he was the best of everyone, always strutting around like he did, just because he was smarter than average and better looking than most of the guys. No one really liked him because he would let no one near enough to him. Even his girlfriend couldn't stand the sight of him after a week. He was a horrible person and I'm not sorry he's dead."

Her tone was flat and toneless; not a breath of emotion had entered it during the statement. Hands laying on her lap, it seemed as though not a single nerve in her body was shuddering.

Tonks smiled grimly. "And there you were worried about insulting the dead."

She quickly glanced over at Charlie to make sure he had gotten her entire statement before continuing her interrogation (as she liked to think of it).

"Do you know much about potions, Miss Adler? Are you skilled in that area?"

Harriet frowned, as though she was unsure about why this question had been asked.

"Yes, yes, of course," she replied. "What sort of Slytherin would I be if I were not? Professor Snape would surely have my head otherwise."

Charlie coughed suddenly, trying to cover a rude-sounding snort. Tonks gave him a half smile before turning back to Harriet.

"Enough to know about strong sleeping draughts?"

Harriet's eyes opened wide. She finally understood where Tonks was going with her questions and she was shocked.

"You mean that Gil wasn't killed by a knife?" she asked, leaning forward in her seat, the mask of indifference gone from her features. "But Ariadne said..."

"That news did not come up until after Miss Vane had rejoined the other prefects," Tonks stated flatly. "Mr. Moriarty was not murdered with the sleeping potion, though I suspect it may have been a stronger dose than was required. The potion put him in such a state of unconsciousness that he would not have even felt the knife when it was stabbed into his stomach."

Charlie would not have believed anyone so pale as Harriet Adler to become more pale than she already was. However, when Tonks said this to the Slytherin prefect, the girl's face drained of any colour it may have had. She looked frightened ... and worried.

"Where, Miss Adler, were you during the time of Mr. Moriarty's death at approximately a quarter to ten this morning?" Tonks asked, trying to take advantage of the other girl's momentary lapse in confidence.

"I was doing my patrols near the end of the train," Harriet replied automatically. "I was on the first shift with Horatio - one of the Gryffindor prefects - and Peter - a Ravenclaw prefect. Gil was supposed to come after..." she trailed off into silence, a single tear trickling down her face.

Tonks nodded as though she had heard something important. "Right-o. Thanks very much for your candidness, Miss Adler. Hopefully, we'll get this all cleared up pretty soon." She stood to open the compartment door for Harriet. "Could you please send in the other prefect who would have been on Mr. Moriarty's shift?"

She turned to look at Charlie, who was reading over his notes with a thoughtful frown.

"D'you think she was guilty?" she asked him, plopping down in her seat.

"I don't know," he replied. "Some things that she said about him at the beginning don't match how she acted at the end. She said that she disliked him, then she cries afterwards? It just doesn't make sense to me."

"Maybe she was more affected by the fact of death of someone she knew instead of the death of an enemy," Tonks hypothesized, twirling a finger through her longish brown hair. "She may not be sorry that he's dead, but she's sorry that someone had to die. Or," she added with a shrug. "She could just be a consummate actress who would be better of gracing the streets of Drury Lane."

From outside the compartment came footsteps stopping at the door, followed by a sharp knock.

"Bring on the next suspect," Tonks muttered to Charlie before crying out: "Come in!"


	6. The Prefects Part Two

**Six**

The compartment door opened to reveal a very short and somewhat plump girl wearing the Gryffindor colours. Tonks supposed (for it is never good for a detective to guess) that usually a huge good-humoured smile would be plastered across the girl's face. At the moment, however, the prefect looked insecure and frightened, to the point that her hands were shaking.

Charlie knew the girl, but only from sight. She gave him a shy smile as she sat down across from Tonks, whose face had not softened an iota, not even for a fellow Gryffindor. Looking at his friend, Charlie thought for a moment that she was channelling the great detective, Sherlock Holmes; that's how deep into the role of detective she had delved.

"Thank you for coming. I know this is a hard time for you," Tonks said, her voice so quiet that Charlie had to lean forward to hear her properly. He wondered which tactic she would be using during this interrogation.

The girl, Irene Westmacott, looked back at Tonks with large brown eyes. "I-I can't believe that this happened," she said with a large sniffle. "Gilbert may not have been the nicest of people, but no one deserves to die like that. It's so horrible!"

"Indeed it is," Tonks answered back. "Which is why we have to find out who did this."

Irene nodded profusely, her mousy curls bobbing up and down with the movement of her head. "Of course, I understand, Nymphadora."

Tonks winced at the sound of her first name, but said nothing to correct the older girl.

"You were going to do your rounds at the same time as Mr. Moriarty, correct?"

The curls bobbed again as Irene nodded. "Yes, I was."

"And where were you while he and Miss. Vane were in the first compartment?"

Irene tilted her head to the side. "With my chums in the third carriage. I went there right after the meeting to catch up after the summer."

"How did you hear about the ... tragedy?" Tonks asked, her eyes narrowing.

Kicking her legs against the seat, Irene did not seem to notice the predatory look on Tonk's face. "Well, we heard the commotion from the front of the train. Just before ten, I think," Irene replied. "Then Bill came around, saying that something had happened and that I had to join the other prefects in the back compartment." She bit her lip and looked down. "That's when he told us what happened. I still can't believe it."

"Some people didn't seem to like Mr. Moriarty very much." Tonks stated, seeming to relax. "What did you think of him, Miss Westmacott?"

For the first time during the interview, Irene straightened up and looked Tonks in the eyes. "Gilbert may not have acted like the nicest of people, but he wasn't vindictive as too many of the Slytherins are. He judged people by their actions, not their bloodline or wealth. He was fair too: if he thought that you were in the right, then he would let you go without a warning, and if you did something wrong, he would aptly punish in an according way." Irene paused to take a breath. "Unlike most of the Slytherins, he knew what had to be done and did it the way he thought was best. Not that he didn't have his negative points, we all do. But I thought that he was better than _some_ people out there."

Tonks leant forward in her seat. "Like who?" she asked with a conspiratorial air.

Irene scowled, if a face as cheerful as hers could ever be so. "That hussy Harriet Alder, of course. She made a number of passes at Gilbert without much success. He was too much in love with his own looks to even bother with her."

Inwardly applauding Irene for this tidbit of information, Tonks shook her head.

"But I heard that Gilbert once had a girlfriend..." she left the sentence hanging to urge the girl on with her wonderfully-detailed answers. Irene had a loose tongue, which was a blessing in an investigation.

Irene rolled her eyes dramatically. "Oh _her_! Well, let me tell you, Catharine Lynley was a perfect match for him if only because she was as self-admiring as he was. But, she held no candle to him for fairness or brains. I wonder sometimes how she even gets through her classes."

From the window, Charlie grinned. If only all their interrogations could go this well.

"Did she take being dumped hard, do you know?" Tonks asked, her voice light and conversational, as though she were gossiping with friends.

"Oh yes she did! You wouldn't believe who vindictive towards him she became. He couldn't go anywhere without her there following him. It was as though she was obsessed with him," Irene answered. "Sort of creepy if you ask me."

Tonks agreed with her, then asked, "How long ago did they break up?"

"Last spring, right before the end of school. Her screams for him to come back to her rang out through the dungeons for a while, I heard." Irene smiled sardonically. "Gilbert had a good reason to wait until the last day. That way, he could get away from her faster."

This last statement worried Tonks, but she tried not to show it. Finally, it seemed, they had found a perfect suspect, but she could not allow the testimony of one person skew her own thoughts and opinions. She and Charlie would have to speak with this Catharine Lynley before too much time had passed.

"Is there anything else that you think we should know, Miss Westmacott?" Tonks asked with a serious tone. "It is of the upmost importance that you are honest with us. It could mean the life of another person if you are not."

The expression on Irene's cheerful face changed to return to the nervous, fidgety one that she entered the compartment with. "No, I'm sure I don't. If I do think of something, though..."

"Then you should tell either us or Bill as soon as possible," Tonks finished for her. "You are now free to go, Miss Westmacott. Could you call in the next prefect for us?"

Irene quickly left the compartment. Neither Charlie nor Tonks said a word to each other. There was nothing for them to say. It seemed with each prefect they spoke to, another suspect was added to the list. If there was one problem with this case, it was that there were too many suspects and not enough opportunities for murder.

The compartment door slid open suddenly and, without knocking, a tall heavily-built boy entered, wearing the colours of Hufflepuff. He nodded briskly to them and sat down across from Tonks, his piercing green eyes looking at the two fourth years, as though he wondered which would speak to him first. His jaw chewed on a piece of gum in the same manner that a cow chews cud.

"Thank you for coming," Tonks greeted him. "And you are...?"

"Terrence Brown," he replied, his voice a low rumble.

"And where were you this morning when Miss Vane screamed?"

He pursed his lips, appearing to think deeply. "I was with the Head Girl and the other Ravenclaw prefect, whatsername," he paused and scratched his head. "Nancy Hastings, yeah, that's her name."

Tonks raised an eyebrow. Obviously, this poor boy had been hit by one too many bludgers on the Quidditch field. She snuck a look at Charlie, who rolled his eyes at her, then went back to concentrating on his transcription of the interviews.

"That's who you were with, Mr. Brown, but where on the train were you?"

"Uh, must have been near the middle of the train," he replied. "Catharine, the Head Girl, you know, she wasn't feeling too well, so me and Nancy were looking after her a bit."

"Oh, that's too bad," Tonks sympathized. "I was wondering where she was during all this. Do you know what was wrong with her?"

He shrugged, a clueless look on his square face. "She was throwing up a lot and kept moaning all bad-like. Nancy told me to leave soon after Weasley told us something happened and she came later, telling us that Catharine had a bit of the 'flu."

Tonks nodded, a thoughtful look on her face. "Did you know Gilbert Moriarty at all?"

Terence shook his head. "He wasn't much into Quidditch. I barely spoke to the chap."

"Alright," Tonks announced while getting up from her seat. "Thanks for your help, Terence. Could you call in Nancy for me now? Good luck with Quidditch this year!"

He grinned, revealing a missing front tooth. "Thanks, I'll get her for you."

When he left, Tonks turned to Charlie. "After seeing him, Char, are you sure you still want to try out for Quidditch this year?"

Charlie smiled weakly. "Being a seeker is very different from a beater."

Before Tonks could reply, the compartment door opened and a very plain-featured girl entered. She was the Ravenclaw prefect, Nancy Hastings, and from the expression on her face, she had something very important to tell them. She stumbled into the room, sweat pouring from her brow.

Tonks jumped from her seat and grabbed the other girl's arm before she fell flat on her face inside the compartment. Carefully, Tonks guided the girl to a seat and sat down beside her.

"Nancy," she said, her voice soft. "What's wrong? Please, tell me if it's important."

The other girl looked up and stared at Tonks through unfocussed eyes.

"The Head Girl," she managed to say, her voice shaking. "She's pregnant."

Charlie dropped his pencil in shock while Tonks froze with fear. "Whose is it?" she asked.

Nancy closed her eyes as though the news pained her. "Gilbert Moriarty's."


	7. The Head Girl

_Many apologies for the slow update. I forgot to update the story on this site, even though it was ready last Thursday. Sorry about that. Enjoy the chapter!_

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Seven**

Tonks' eyes opened wide while Charlie's jaw dropped at the news Nancy had given them. The Head Girl was pregnant with Moriarty's child! How could that be possible?

"Are you sure of this?" Tonks asked, struggling to keep her voice even.

"That's what she told me," Nancy answered, her cheeks flushed with both apprehension and embarassment. "She said that there could be no doubt to the identity of the father."

Tonks nodded, still feeling shocked. "Do you know how ... advanced she is in her pregnancy?"

When the prefect frowned, Charlie spoke up. "What sort of symptoms was the Head Girl showing? Other than throwing up, of course." Tonks glanced at him with a raised eyebrow and he hurried to explain. "I've watched my mum go through a few and I sort of can guess by the symptoms."

Nancy pursed her lips, as though carefully thinking back to what she had seen. "Well, I couldn't see much because she was wearing baggy clothing. Even her robes are larger than they need to be."

"At least a few months then," Charlie reasoned. "Three or four, surely."

Ignoring Nancy entirely, Tonks sat up straight, her eyes bright. "But that would mean that he - well, you know - while he was still going out with Catharine, his ex-girlfriend."

"What are you talking about?" Nancy exclaimed. "Catharine Lynley is the Head Girl!"

Once again, Tonks found that she was greatly surprised. She silently berated herself for having not known that tidbit of information beforehand. However, this news also gave the investigation the one thing it had been direly missing.

"And that," Tonks said, a smile growing upon her face. "Gives us a definite motive."

She turned to Nancy. "Thank you very much. We'll ask you some more questions later. Would you kindly tell Bill that we'd like to see him?"

As soon as the Ravenclaw prefect had shut the door, Tonks leant forward in her seat.

"We'll have to leave off of the prefects for now until we've spoken to the Head Girl. I have a feeling that leaving the prefects alone will be fine. If any of them are involved, and I feel that some of them are, they will not want to reveal their crime to those not privy to the plan."

"And you think that it's the prefects who've done this?" Charlie asked her.

"Either at the will of Miss Lynley or in defense of her," Tonks said by way of answering. "The only problem is that I don't know which of them are responsible and which have been caught up in a vicious circle of events. Nor can I think of which of them planned the whole charade."

A strange look crossed Charlie's face. "Tonks, I think you're beginning to sound like one of those American police detectives."

Tonks tilted her head to the side. "And how, my pureblooded friend, would you know that?"

Charlie bit his lip, realizing that his knowledge of the muggle world was greater than he'd ever care to admit.

"My dad likes that sort of thing, remember?"

Grinning widely, Tonks said, "Of course." A more serious tone drifting into her voice, she added, "Now, when the Head Girl is interviewed, I'd prefer to go alone to make her feel more comfortable, especially with her situation as it is. She might not say as much with a boy in the room."

Disappointment was evident upon Charlie's freckled face, but he managed to keep it out of his voice.

"What do you want me to do while you're talking to her?"

Tonks had known ahead of time that Charlie would not enjoy being left out of things and had planned to let him search for a pearl of information that perhaps had been missed.

"You will be interviewing the train's staff," she told him brightly. "The porters and the trolley witch especially. They may have seen someone or something that makes a bearing on the case. Make it sound routine, like we're just checking up on things. Being too serious could frighten them."

Charlie nodded and stood, closing his notepad. "I'll do that right away then. Good luck, Tonks."

Just as he was leaving the compartment, Bill entered looking harried and disgruntled.

"What is this about Catharine?" he asked, taking the seat across from Tonks. "Hastings was barely able to speak much less explain her strange behavior."

Tonks chewed on the inside of her cheek, trying to figure out the most appropriate way to tell him someone else's secret.

"It's something that might get the Head Girl into a very serious predicament, even more so than the one she is currently in," she finally said quietly.

"We need to know what happened, though," Bill argued, his brow furled. "There's only a few hours left until we arrive in Hogsmeade and I'd like to have the matter cleared up by then. I've already sent an owl to Dumbledore, outlining the problem." When she didn't interject, he continued. "The train will be met by two Aurors, who will investigate and arrest whoever did this."

"But by then, all the students will have left the train," Tonks added. "Making it harder to find the conspirators."

Bill nodded. "Now tell me, what's wrong with Catharine?"

Turning to look out the window, Tonks whispered, "She's pregnant with the child of the dead prefect."

Bill swore profusely and buried his head in his hands. "I should have guessed that. She acted like she was hiding something," he admitted.

"I was just going to talk to her, but I thought you'd want to know why it's so important," Tonks said, looking back at him. "I believe that her pregnancy plays a big role in Moriarty's death. It's an excellent motive for murder, especially since he dumped her."

His eyes rose to meet hers in question. "Do you think that Catharine had a hand in Moriarty's death, then?"

Tonks shook her head. "I don't think so, but I'll be able to give you a better answer once I've spoken to her."

"Then what are you doing sitting here?" Bill asked, mockingly raising his eyebrow.

With a grin, Tonks saluted. "Right-o, sir. I'll get right on to that."

Leaving Bill to return to the prefect's compartment, Tonks began walking towards the back of the train, where the Head Girl was supposed to be. She finally found Catharine Lynley sitting alone, eating a bar of chocolate as though it were her last. Catharine was slouched in her seat, looking out of the window, her face red and stained with tears. Tonks guessed that the other girl had just learned of her ex-boyfriend's death.

"Hi," Tonks said, entering the compartment and sitting down across from Catharine. "Miss Lynley, I'm sorry to bother you at this time, but it's important that I ask you some questions."

Pale blue eyes rose to meet hers. "So it's true then, Gil's gone. I didn't want to believe it. I mean, I always thought that he'd come back, but now - " She broke off, her eyes filling with tears.

With a ragged breath, she continued. "It was a stupid thing, our break-up. We argued over something trivial, then he told me that it's over, that I wasn't 'logical' enough for him. It hurt, yes, but for the entire summer I've been waiting for him to owl me or just talk to me. Anything... But that's impossible now. I'll be left with nothing. Who wants a girl with a child anyway?"

Tonks swallowed, feeling immense pity for the Head Girl. "I'm sorry. It'd be a lie if I said that I understand what you're going through, but there is something I need to know... How many people know of your - your condition?"

Catharine frowned, wiping a tear from her cheek. "What do you mean?"

"Have you told anyone that you're pregnant?" Tonks blurted out.

"No, no, of course not," Catharine replied, her voice now calm. "It would compromise my position as Head Girl, which I suppose will be revoked now. Nancy figured it out for herself, so I couldn't very well lie to her."

This answer posed a problem for Tonks, who had been hoping to easily find someone connected to the motive that sat right in front of her. Perhaps Catharine was simply too convenient. There had to be another, far greater reason that Gilbert Moriarty had been murdered. With only two and a half hours to find both motive and murderer, Tonks had much work to do.

"Tell me about Gilbert," she asked, leaning forward in her seat. "What was he like?"

A rather dreamy expression crossed Catharine's face. "He was perfect. Good looking, though just a little conceited about it, but one can't blame him, not with the way his body was perfectly toned and his hair like spun gold. And his eyes, Merlin ... nothing like them can ever be seen again on this earth."

Just as Tonks was ready to throw up, Catharine continued, her voice soft with remembrance. "I don't blame him for dumping me, you know. It would be stupid of me to even try. His ambitions were great: he dreamed of climbing the Ministry of Magic ladder and maybe even becoming the Minister. And he would have deserved it, too. He was so incredibly smart - not just book smart like some people thought - he could conjure spells and mix potions like you couldn't believe." She paused for a moment, smiling to herself. "Gil was so chivalrous as well, helping old ladies across the street and protecting the younger girls from being teased by the upper years. I've never known anyone like him." She finished with a romantic sigh, her eyes sparkling.

The expression on Tonks' face revealed the mixture of disgust and disbelief she felt. Most disturbingly, Catharine's description wasn't too far off the mark, but it only saw the good side of Moriarty's character, which was, perhaps, the only part of him that Catharine ever saw. The Head Girl was star-struck, and there was no possible way to get beyond that.

Much of her pity vanished in the blink of an eye, replaced by great discomfort. _How could someone be so blindly in love? What was the point of letting that happen to yourself?_

"Do you know anyone who would want to kill him?" she finally asked, breaking into Catharine's seemingly blissful reverie.

The Head Girl blinked, surprised at the question. "Well, I could never understand why _anyone_ would want to kill such a person as Gil was, but the only person I know who would is Harriet Adler. She wanted him badly and everyone knew it. I guess she just couldn't handle the fact that he had his attention in other places."

Eager to leave, Tonks stood and thanked Catharine for her help. Perhaps, within her grossly romantic narrative mixed with serious answers, there was a tidbit of information that the Head Girl had revealed that could lead to finding Moriarty's killer.

The only problem was that, the more she heard about his personality and actions, the less she liked the handsome and clever Slytherin prefect. The perfect murder for the perfect person. It fit quite well, almost _too _well.


	8. A Change in Events

**Chapter Eight**

Tonks was very confused. She did not like the way this case was turning out at all. There were too many suspects, too many motives, too many things that the victim had done to make others dislike him ... too much of everything that made the case too complicated. She felt as though not even the Great Detective could solve this one easily, or that Hercule Poirot would have to work his 'little grey cells' to their maximum to find all the answers. Tonks was certainly clueless, no matter how confident she pretended to be.

Thinking back on all the murder mysteries she had read, one thing she remembered was that, when a detective found themselves in a mental block, they looked over all the evidence, trying to look for clues they may have previously missed. In her mind, Tonks counted the pieces of evidence that she had found in the compartment - not hearsay, but concrete articles that could convict the killer.

First of all, there was the knife which, for safe keeping, she had placed in her pocket, still wrapped in tissues. There was one clear fingerprint upon it, she was sure, and could therefore be used as evidence against whomever she accused. Secondly, there was the vial which had once contained the sleeping potion. Before leaving the compartment, she had hidden it on the luggage rack, just in case the porter proved to not be as watchful as he should have been.

There was also the body itself, which was stabbed _after_ the potion was administered. That could mean any number of things, such as the basic fact that it kept Moriarty from crying out while he was attacked. But it could also mean that the attacker would not have been strong enough to oppose any defence that Moriarty put up for himself, with his wand or otherwise. As of yet, Tonks did not know how the potion was administered to Moriarty, but she hypothesized that Charlie would find out from the Trolley Witch if Moriarty or another occupant of the compartment had bought any food from her.

There could very well be something in that compartment that Tonks had missed in her cursory search for evidence. After discovering the vial, she had practically disregarded anything else in that compartment except the knife. For all she knew, there could be a piece of crucial evidence still inside.

That left her only one choice: to return to the scene of the crime.

Her footsteps filled with purpose, Tonks made her way back the front of the train, passing compartments filled with Hogwarts students, old and young, big and small. Most of them were talking to each other about their summers, others were taking a moment before the train arrived to catch up on sleep, while others were studiously reading their new textbooks. Tonks was amazed at all the different people who attended Hogwarts; they came from all walks of life to one place for the singular purpose of learning magic. Yet, of all the people she saw, she knew that one (or possibly more) of them was a ruthless murderer who would go any length to cover their tracks.

A few minutes later, she arrived at the very first carriage of the train that now contained the lifeless body of a school prefect. By the door, ramrod straight, stood one of the porters. He smiled when he saw Tonks approaching.

"Hello, miss," he greeted her. "All's been well here."

"Thanks for your trouble," Tonks replied. "Could you stay longer? I may have to run off again soon. Sorry 'bout that."

"Don't apologize, miss," he said, his smile broadening. "There's still a couple hours until my services are needed elsewhere."

A sense of time suddenly came back to Tonks. She only had a limited amount of time until the train pulled into Hogsmeade station and the Aurors took over the investigation from her. If there was one ambition she had, it was to show that she was good at _something._ Perhaps it would even lead to a future as an Auror, though, she didn't see herself having much chance of passing the gruelling tests she'd heard were involved in that process.

"How much longer until we arrive?" she asked the porter.

He took a silver pocket watch from his waistcoat. "Two hours, maybe three at the most. It's been good weather this time around, we've been lucky."

_Not lucky from my perspective_, Tonks thought, hiding her frown from the porter.

"Right-o," she told him instead. "If I need anything, I'll ask you."

He nodded and leaned back against the doorframe, gazing out the window at the rapidly darkening scenery. Night was approaching quickly. Too quickly for Tonks' liking. She knew that with the darkness, the murderer's trail would be better concealed. Tonks' own safety was also at risk the closer she got to solving the case.

Perhaps she was into something that could become too difficult to escape.

But it was too late, she was in too deep. She had to finish this case, if not for the victim, then for justice itself. No one deserves to die like this, even when they have done others wrong as Gilbert Moriarty had.

And she would be the one to find who had done the terrible crime.

With a new and far stronger resolve, Tonks nodded to the porter and entered the compartment, joining its single - and very dead - inhabitant. Upon turning to look upon this person, she noticed something was very wrong. She could have sworn that she had left his arms folded across his chest as a sign of respect. Now, however, the left arm was splayed out on the floor.

_Perhaps it's just me_, she first thought. Carefully stepping over the pool of blood on one side of the compartment, she looked around, hoping to find something else that had been moved, anything that could tell her someone had been in the compartment after she and Charlie had left it. Yet, other than that arm, there were no differences.

_Look again_, her mind told her. A prickling at the back of her neck warned her of something else out of place. _But what was it?_

From the window, she used the fading light to look at the compartment again, but this time with a more open eye, not looking for details, but for an overall picture of the entire scene. There was the body, on the floor by the right-hand seat. The blinds were tightly shut, exactly as she had left him. To the left of the body was a pool of blood, which had seeped from the knife wound in the side of his stomach. There was ...

Then she saw it.

A partial footprint from the drying blood. That is why she hadn't seen it before, because the changing light hadn't revealed it to her, but upon closer examination, there was a footprint now beside the body where she knew there hadn't been one before.

Moving beside the body, she knelt over the footprint, bringing out her magnifying glass in order to see it better. Just as she did so, the lights in the train flickered on, and she saw the delicate outline of a single footprint, smeared upon the compartment floor.

She leaned back against the seat, her mind exploding with thoughts and questions. _What did this mean? _she asked herself. _Who did this, and more importantly, why? What are they after?_ There must have been something at the scene that had incriminated someone that they were willing to risk their cover in order to get it back. But what was it?

Tonks closed her eyes and remembered back to when she had first entered the compartment. What had been under Moriarty's left arm, other than the knife wound? Could it have been the knife itself that they were after? If so, then why leave it there in the first place?

There were far too many questions without answers. Before she tried to discover _what_ was missing, why not first try and find _who_ had taken it?

She stood up energetically and rushed out of the compartment, badly startling the porter, who had been taking a quick nap while leaning on the wall facing the window.

"What happened when I was gone?" Tonks burst out. "The body has been moved."

The porter's cheeks turned bright red as he quickly stood at attention, looking at Tonks as one would a particularly strict drill sergeant.

"Well, miss," he began nervously. "You see there was a commotion in the hall by the lavatories. A girl had fainted for some reason or another, and I was called to help."

That made sense to Tonks, especially since the lavatories were close by.

"And did you have to leave your post for that?"

"Only for the shortest of time, miss," he replied. "Barely a minute."

Tonks bit her lip. She had big hopes for her next question.

"When you were coming back, did you notice anyone close to here?"

He nodded energetically, glad to be of assistance. "Yes, yes, miss, there was. It was the same girl that asked me for help, now I think of it. Not the one that fainted, but the one with her, if you know what I mean."

Tonks smiled brightly. This was her chance to finally find the murderer, or murderers, as the evidence was telling her.

"And can you tell me what she looked like?"

The porter returned her smile with a wide grin. "Indeed I can, miss."

A few minutes later, Tonks was striding down the row of compartments, a few sickles poorer, but much richer emotionally and mentally. All the loose strings were tying together, with her hands holding the end that led to the truth.

She had found the killer. Now all she had to do was prove it.


	9. The Curtain is Lifted

**Chapter Nine**

"Are you _sure_ that you saw nothing suspicious?" Charlie asked one of the porters, his temper on the edge since none of them seemed to know anything worth while. He wanted to find at least one piece of information to help Tonks find the killer.

"N-n-no, s-s-sir," the young porter stuttered, his hands shaking uncontrollably.

Charlie sighed. "Fine, you can go. Do you happen to know where I could find the trolley witch? She's the last I have to speak to."

The porter nodded wildly. "Y-y-yes-s-s," came the reply. "S-s-she s-s-hould-d b-b-be in-n the b-b-back-k wat-t-ting for the t-t-train t-t-o c-c-come to H-h-h-hog-gsmead-de."

It took a moment for Charlie to understand exactly what the porter had said since the man's stutter was so pronounced, but afterward, he thanked the porter for his help and walked down the long walkway to the far end of the train. On the way, he saw Irene Westmacott ahead of him in the hall. He called out to her and she turned, a bright smile appearing on her face.

"Charlie!" she exclaimed. "What a pleasant surprise."

"What are you doing out in the hall?" he asked her, not bothering to waste time with greetings. He had seen her barely an hour before.

"I had to use the lavatory," Irene replied, her voice calm and level. "It's all this excitement, you know, and the anxiety as well." After a short pause, she continued. "Have you found anything interesting yet?"

With a shrug, Charlie said, "Not really. Nothing that you don't already know."

She nodded. "I see," she said, the slightest degree of disappointment appearing on her brow. "Not that you would tell me if you knew, anyways," she added.

"Of course," Charlie answered, forcing himself to smile at her.

_Something wasn't right..._

"Here," he told her. "I'll walk you back to the prefect's compartment, Irene. You don't know if the killer is still on the loose. You never know, he could be targeting prefects, not necessarily just Moriarty."

"Alright," she said, the disappointment replaced by frustration.

Charlie was surprised and unsure. This didn't seem like the Irene he and Tonks had interviewed earlier. What had happened to her since that interview? Had she been threatened in some way? Or had she figured out who the killer was? In any case, Charlie resolutely walked her back to the prefects' compartment, nodded to his brother once they arrived. Bill raised his hand slightly, then went back to speaking with one of the two prefects Charlie and Tonks had not yet spoken to: Horatio Dalgliesh. Not too far from the Gryffindor prefect sat Nancy Hastings and another unknown prefect, most likely Peter Jury, a Ravenclaw prefect. For the most part, they were all quiet except for the occasional sniffle from Ariadne and the quiet whispers between Jury and Nancy. The other prefects were silent.

As he left the compartment and continued, Charlie wondered if he and Tonks should have continued their questioning of the prefects instead of going off on separate leads. He was curious to know what Dalgliesh and Jury had to say about the dead Slytherin. Perhaps there had been rivalries, jealousies...

Or perhaps he was spending too much time with Tonks and her murder mysteries.

Shaking the obtrusive thoughts from his head, Charlie continued down the length of the train until he arrived at the final carriage, known by some as the caboose. Inside, huddled around a table, sat some of the train's staff, taking a short rest before they were to arrive at Hogsmeade. The clock on the wall divulged that time was short: there was perhaps an hour until the train was due at the station.

He smiled duly at the group of adults and politely asked to speak with the trolley witch. A buxom and pleasant-looking woman stood up, introducing herself as Dorothy Doyle, trolley witch for the past decade or so. When Charlie asked whether there were a private place for him to ask her some questions, she turned to the other workers and, with a toss of her head in the direction of the door, sent them out.

"Would you like a cup of tea or glass of soda, young man?" she asked him, her smile kind and motherly. She reminded him a bit of his mother, who treated guests like royalty.

"A soda would be great, thank you," he responded, hoping that taking the witch up on her hospitality would make it easier to question her.

Once they were settled with their drinks, Charlie took out his notebook and charcoal.

"Mrs. Doyle," he began. "Did you stop at the very first compartment of the train around 9.15 this morning?"

"Yes, I did," Dorothy told him. "There were three people in it at the time, but I didn't stay there very long since one of them was sleeping. Poor boy needed some rest before school, I suppose. I hated to disturb him, especially since the other two said they didn't want anything."

Charlie choked on his drink upon hearing this, and Dorothy had to pat him on the back a number of times before he could breathe normally.

Once he could speak, he asked her, "Do you remember what these students looked like at all?" Hopefully, the lady had a very good memory. Suddenly, the whole case seemed to rest upon the broad shoulders of the trolley witch.

"Indeed I do," she replied with a broad smile and she went on to describe them in a fair amount of detail that surprised Charlie greatly. Or perhaps it was not so much the _amount_ of detail she gave that surprised him, but rather _those who were being described_. After Dorothy had completed her description, Charlie jumped up, profusely thanking her for her kindness and assistance in the murder investigation. Hurrying from the room, he practically ran down the walkway towards the very front of the train.

He met Tonks in the walkway. Rather, they walked into each other as neither was looking where they were going since their minds were caught up in the matter at hand. Without realizing that they both had learned the same information in grossly different ways, the two friends began talking at once.

"I know who did it!" Charlie exclaimed in a voice barely above a whisper.

"You'd never guess who is responsible!" Tonks told him excitedly, then quickly became quiet when she finally understood his words.

"Are we speaking of the same person?" she asked.

"People, you mean," he quickly corrected her. "There were three involved, though there could be more, I suppose."

Tonks hurriedly revealed her discoveries, after which Charlie told her what he had learned. Upon hearing the same name and physical description for one of the people, Charlie said, "It should have been obvious at the beginning. The way she acted that whole time..."

"Yes," Tonks interrupted. "But sometimes the most obvious answer is the most difficult to find."

"I still can't understand why she would plan all of this," Charlie wondered.

Tonks smiled somewhat stiffly. "That's just something you'll have to ask her."

Discussing aspects of the case and how they could entrap the suspects, Tonks and Charlie made their way to the prefects' compartment, where five innocent and three guilty awaited news of the case or the arrival of the train. Whichever happened to occur first.

Upon entering the compartment, the two detectives immediately felt the tension which filled the air like electricity. The Gryffindor and Hufflepuff prefects sat on one side, while the two Ravenclaw prefects and Harriet Adler sat on the other, the Head Girl by the window beside Nancy. Standing at the window, directly between the two benches, was Bill, who was beginning to look stressed, a rarity compared to his usually calm demeanor.

"Well?" he asked the two fourth years with the slightest tone of impatience in his voice. "What have you discovered? Anything to clear up this mess?"

Charlie glanced beside him at Tonks, who was nodding, a grim expression on her face. "We know everything: what happened, how it was done, and most importantly, who did it." she said, her voice quiet, yet infinitely strong.

"Then tell us!" Bill ordered, his voice cracking as he said it.

Tonks took center stage. Charlie was all but forgotten as Tonks began to explain all the elements of the case.

"Before I reveal the identities of the guilty parties, I'll tell you how it was done. In effect, the clever and supremely devious plans that led to the death of Gilbert Moriarty." Her gaze took in all of the collected suspects and people closely involved with the victim, as though she were trying to obtain any clues from them.

"All of this started over the summer when, quite by accident I presume, the future Head Girl, Catherine Lynley, let slip that she was pregnant most assuredly with Moriarty's child. It was well known in the upper years that Moriarty had tired of his girlfriend, or rather he was tired of having a girlfriend. I can only suppose that he felt that it was getting in the way of his studies. From what I've heard of Moriarty, he was very ambitious, aspiring to become Minister of Magic." The slightest smile played upon her face for a moment, then vanished as soon as it had appeared.

"It was then that our killer had an idea, perhaps which started as merely a way to get revenge upon Moriarty for leaving his girlfriend in such a way. It was dishonourable, something no one from a pureblood family should do. This person was disgusted with Moriarty's lack of feeling for anyone but himself, and so their initial idea grew into something greater, something far more deadly. They began making plans to rid the world of Moriarty altogether. But they could no do it alone, so they made arrangements to meet someone they knew, someone who had the ability and the audacity to be able to pull it off."

She paused for a moment, in which they could all hear the silent sobs of Catherine, who had know realized that this had all happened because of her.

"By the time we were all boarding the train," Tonks continued. "There were three conspirators involved, all with a grudge against Gilbert Moriarty, and all willing to assist in removing him from their - and everyone else's - lives. One had beforehand prepared a strong sleeping potion to ensure that Moriarty would not cry out while another carried with them a knife. This one, in fact." With this statement, she took from her jacket pocket the tissue-wrapped knife, and carefully, without disturbing the blood or fingerprint evidence, displayed it for the group to see.

There were many gasps as the blood was noticed - a brownish-red stain that spread across the blade of the knife. Nancy Hastings turned away, burying her face in the shoulder of her fellow Ravenclaw prefect Peter Jury. Terrence Brown frowned, a mournful look in his eyes. Bill made a strangled sound in his throat, his hand resting gently on Catherine's thin shoulder. Harriet Adler looked once at the knife, then dropped her eyes to the floor, a single tear making a trail down her cheek. Irene Westmacott sat stiffly in her seat, her face entirely devoid of expression, while beside her Ariadne Vane burst into tears. Horatio Dalgliesh stared at the knife, his mouth wide open.

"I'll be damned," he exclaimed, rising from his seat. "That's my knife!"

Charlie instinctively moved to protect Tonks in case the Gryffindor prefect tried to attack her, but there was no need for his protectiveness.

"Are you sure that it's yours, Mr. Dalgliesh?" Tonks asked Horatio, stepping towards him to give him a closer look at the murder weapon.

He nodded. "Yes, of course, I'd recognize the hilt anywhere. It's been in the family for generations - nearly five hundred years."

Charlie, who had not expected this, glanced over at Tonks to see if she was also surprised, but all he saw in her face was pure excitement. It seemed as though she had expected this turn of events.

"And why, may I ask, did you bring it along with you?" she asked Horatio.

He looked up at her, his eyes filling with comprehension. "Someone asked to see it."

Tonks was nodding sympathetically. "I see. And when did you discover it missing, Mr. Dalgliesh? Or did you give it to someone?"

Horatio muttered something unintelligible, his gaze turning to examine the floor.

"You lost it, didn't you Horatio," Tonks said quietly.

When he nodded, she looked at the rest of the group. "I know from my investigation that the perpetrator - or rather the mastermind - of this crime was female, even though I believe the one who held the knife itself was male. The girl who did this held a deep and passionate grudge against Gilbert Moriarty, hating him through and through. From what I've heard, there are a number of girls who would have felt this way, particularly since he was such a popular person with the ladies, yet ignored them entirely. One of his biggest fans was you Miss Adler."

Harriet looked up suddenly, her grey eyes widening in shock. "Surely you don't think - " she began, but Tonks briskly cut her off.

"You had a motive, Miss Adler. A strong one, some people have told me. You liked Gilbert a lot, and you were upset when he went off with Catherine Lynley and probably felt even worse when you found out she was pregnant!"

"That's a lie!" Harriet cried, jumping from her seat. "How could you even think of such a thing! I loved Gilbert, that's true, but I never _ever_ could have hurt him!"

Tonks smiled. "I know that, which is why I never really suspected you. It was too obvious when we were interviewing you that you liked him, but wished to hide it."

A perplexed expression on her face, Harriet sat back down.

"Of all of the other female prefects," Tonks continued. "Only Nancy Hastings had a perfect alibi - one that checked out as well. She was with the Head Girl from the time they boarded the train until the time Nancy came to see me."

"Wait a minute," Irene argued. "But didn't I tell you that I was with my friends the entire time? How can you then say that I have no alibi?"

Tonks turned to the Gryffindor girl. "Well, I can say it because it's true. When I asked your friends, they said that you left them about fifteen minutes after the train left King's Cross because you had to go on your rounds as a prefect. Then you came back a few minutes before Miss Vane's scream. Yet you told me otherwise."

_"You were going to do your rounds at the same time as Mr. Moriarty, correct?"_

_The curls bobbed again as Irene nodded. "Yes, I was."_

_"And where were you while he and Miss. Vane were in the first compartment?"_

_Irene tilted her head to the side. "With my chums in the third carriage. I went there right after the meeting to catch up after the summer."_

_"How did you hear about the ... tragedy?" Tonks asked, her eyes narrowing. _

_Kicking her legs against the seat, Irene did not seem to notice the predatory look on Tonk's face. "Well, we heard the commotion from the front of the train. Just before ten, I think," Irene replied. "Then Bill came around, saying that something had happened and that I had to join the other prefects in the back compartment." She bit her lip and looked down. "That's when he told us what happened. I still can't believe it."_

"You really couldn't believe it, could you?" Tonks asked the older girl. "You couldn't believe that your plan actually went through; that Gilbert Moriarty was indeed dead."

As the other prefects looked shocked and surprised, and Ariadne Vane burst into tears once again, Irene rose from her seat and charged at Tonks like an angry lioness. Then she pushed past the younger Gryffindors - Charlie grabbed at her but missed - and ran out of the compartment, hurrying towards the front of the train.

"She's going to warn her other conspirator," Tonks said, her voice strangely harsh. "Terrence, Horatio, Peter, can you help Charlie capture a seventh year Ravenclaw near the back of the train. If I'm correct, he changed compartments soon after Charlie saw him. Irene's going to the wrong place."

"But who will go after her?" Charlie asked her.

"I will," she told him, beginning to move off after the escapee. "Now hurry!"

* * *

_One more chapter..._  



	10. Case Closed

**Chapter Ten**

Tonks took off down the walkway at a run, just barely keeping the quickly-moving Irene in sight. Pretty soon, however, Tonks knew that the other girl would run out of space to run once she reached the front of the train. Irene would then be as dangerous as a caged wild animal. As she ran, Tonks took her wand from her jacket, hoping that she would not need to use it.

Students in the compartments lining the walkway were peeking out the doors to see what the noise was about. All they saw was an plump brunette Gryffindor being chased down the train by a pink-haired girl in muggle dress. But what they did not see was what occurred at the end of the walkway, when Tonks finally caught up to Irene, who had stopped at the carriage door to wrench it open. Darkness was setting in around them, the sun having set nearly a quarter hour before, and the moors and dales of the north were hardly distinguishable. Stone fences and herds of sheep flew past the train, mere shadows in the growing twilight.

Irene threw herself through the door and fell heavily against the waist-high rail that separated the small platform from empty air. It was nearly impossible to hear anything over the sounds of the engine and the air rushing past them. Irene looked back to see Tonks blocking the doorway back into the train: her only safe exit.

"Don't do this, Irene!" Tonks cried. "It's not worth it!"

The fierce look on the Gryffindor prefect's face was the only thing that kept Tonks from using physical strength to force her back into the train.

"Do you think I'm going to go back just to get myself thrown into Azkaban?" Irene yelled over the blaring of the train's horn. "I'd rather _die_ than suffer there because of stupid Moriarty! He had what was coming to him."

"Killing yourself as well isn't the answer, Irene!" Tonks returned.

But Irene did not reply. Instead she turned as though to jump.

"_No_!" Tonks shouted, snatching at the other girl's robes. She put all of her strength into pulling Irene back from the rail, which was not at all easy since Irene was not small and was far stronger than she seemed at first sight.

"Get off me!" Irene screeched, fumbling at the hands grasping her robes. She freed herself and turned, her hands reaching to claw at Tonks' face. As Tonks reached up to protect her face, Irene saw the smallest gleam from the knife - the murder weapon - in the pocket of her adversary. In an instant, she grabbed the knife and held it between her and Tonks.

Tonks backed up, her eyes upon the dangerous blade.

"Surely killing one person is enough for you?" she asked Irene.

The Gryffindor prefect's eyes were now wild with fear and hatred, her once-pleasant face now filled with a terrible horror. She knew she was cornered, but she would not go down alone.

"I didn't kill him!" she shrieked. "I wasn't the one with the knife in my hand!"

"But you planned the whole thing," Tonks added, her voice shaking. "It was all your idea, and you got Ariadne to help out, same with that seventh-year Ravenclaw."

"It was him! He was the one who did it, not me!" Irene defended, brining the knife up to the level of Tonks' throat.

"Did you even care that you were setting up an innocent person? Harriet loved Moriarty, but she never could have killed him. You must have known I would find that out eventually." Tonks persisted. She was hoping to prod Irene into making a final move or perhaps even make a full confession of the crime.

"I hated him!" Irene suddenly screamed, her head tipping back to cry her words to the open sky. "He flaunted himself in front of everyone, not caring whose hearts he broke. He would have ruined Catherine in more ways that he already did! Someone had to do something!"

"Murder can't be that something," Tonks said quietly.

From inside the carriage came the sounds of people running towards the front of the train. Tonks heard it at the same time as Irene, who made her final move, lashing the knife at Tonks with all the strength which remained to her. Tonks stumbled back, unable to make much use of the wand in her hand. Falling hard against the rail, Tonks felt it strain under the force and silently prayed that it would not break. Irene hurried forward, the knife erect in her hand and a murderer's look in her eyes. She fell upon Tonks, who was still struggling to keep her balance, and tried to push the knife at Tonks' unguarded throat. Just in time, Tonks was able to grab the wrist which held the knife, using all the muscle she had in order to keep it from making her a match to Nearly-Headless Nick. However, Tonks could feel her centre of balance begin to push further back upon the rail. If she could not get away from Irene, most likely she would be thrown off the train to fall to her death on the stony ground below.

The door to the platform was thrown open and three people spilled out. Someone knocked Irene over the head with a heavy object, quickly grabbing the knife before it clattered to the ground and fell off the moving train. Tonks was pulled away from the rail, her head swimming.

"Are you alright?" Harriet Adler was asking her, leading Tonks back into the carriage.

"Get her to a warm place," Charlie said when Tonks didn't reply. "Ask one of the porters to get her something."

Before Tonks fainted into oblivion, she recalled seeing Charlie and Bill drag an unconscious Irene into the train, not caring if her head or feet hit the doorframe. She also saw the worry in Charlie's eyes as he glanced towards her. She also saw the knife in Bill's hand, imagining the bloodstains to be her own.

* * *

When her eyes reopened, she first noticed the lack of movement, which meant that the train had stopped. They must have arrived at Hogsmeade while she had been unconscious. As she struggled to sit up, a slightly blurry face came into view. 

"Are you alright, Tonks?" Charlie was asking her, his voice filled with worry.

"What happened? Why did I faint?" she managed to ask him.

Slowly, her eyes were beginning to come into focus and she realized she had been lying on the seat in a compartment. No sounds of students talking or walking around could be heard.

Charlie shrugged. "It might have been the fact that you nearly fell off the train."

Tonks peered at him to see whether or not he was being sarcastic or not. Before she could say anything in reply, however, a tall, grizzled man entered the compartment. His face was so scared that he looked as though a chef had experimented chopping techniques upon it. A large piece of his nose was missing as though a bite had been taken out of it by an animal with very sharp teeth. One of his eyes was dark and beady, glaring into a person with suspicion, while the other eye was bright blue - obviously not his real eye - and spun around, seeing everything and nothing at the same time.

This man nodded to Charlie, then looked down at Tonks, now sitting up.

"You're the one who figured it out," he said, almost accusingly, his voice a low growl.

Tonks swallowed, her mouth suddenly dry. "Yes, sir. I was."

"How'd you do it, might I ask? It's not everyday that you hear of a kid like you solving murders." His magical - for that's what it had to be - eye stopped its route, looking straight at her slightly maliciously.

"I - I," suddenly she found herself lost for words in front of the man. He could be no other than the famous Auror Mad-Eye Moody, who had caught more Dark wizards, especially after the fall of You-Know-Who, than any other before him.

"It was that book," Charlie spoke up, clearly not so nervous in front of the Auror. "Remember? That one you were reading about the murders on the train?"

Tonks reached into her jacket's inner pocket and pulled out the yellowed paperback novel. "Yeah," she said. "It was this book that helped me. The ending's not quite the same, but it still was a crime of deliberation and passion." She looked up at Moody, suddenly remembering something else. "Sir? Did you get the knife with the fingerprints? And the glass vial as well?"

The Auror nodded, the tiniest of smiles (or what one could suppose was a smile, with the way his face was so distorted) appearing on his face. "Indeed I do. Quite the detective work you did, young lady. Them at the school will make an Auror of you yet. Lots of promise you have."

Tonks' jaw dropped. "You mean it? I could be an Auror?"

Moody laughed, an eerie sound that reminded Tonks of Count Dracula crossed with Frankenstein. "I'll expect to see you in a few years up at the Academy." He left soon after, meeting an even taller, dark-skinned man in the walkway who grinned at Tonks, then followed after the older man.

"So how did you figure it out?" Charlie asked. "How did you know that the Ravenclaw boy had something to do with it."

"Another red herring," was Tonks' reply. "He was trying to lead you off somewhere else, just like Irene did with her finger-pointing at Harriet Adler. By pretending to be open with his information, he was really trying to cover up his deceit."

"What did Ariadne Vane have to do with it then?"

"From the amount that she cried while I was explaining what happened," Tonks began. "I realized that she had not really _wanted_ to be involved with the entire fiasco, that she was bullied into it by Irene, who needed to be away from the scene as soon as possible. It was also Irene's idea that she should plan the murder, but not actually wield the knife. Very clever, it was."

"What led you to the Ravenclaw, though?"

"When you first mentioned him, I was a little wary of his assuredness of what he was saying. It just didn't seem right," Tonks told him. "So, when you went off to talk to the train staff, I went over to see him. He acted so shifty I'm sure an American gangster could learn a thing or two from him. Anyway, he let slip that he knew Irene. As soon as he said that, I knew."

After a short moment of silence, Charlie asked, "What do you think will happen to them now?"

"Irene and that Ravenclaw - Adam I think his name was - will go to Azkaban or something similar. Most definitely they'll have to go before the Wizengamot. Ariadne, however, probably will get off easily since she was forced into it. Besides, she didn't have a very large role in the plot, just to make up the initial story about finding the body and cause a distraction when Irene wanted to retrieve the potion vial."

Charlie shook his head. "I still can't believe that all this happened."

"It can happen anywhere," Tonks said. "And usually in the place you'd least expect it to."

Once they were off the train and had been taken to the school, Tonks felt strangely distant from the rest of the world. She had been so enthralled by the mystery that, now it was over, she didn't know what else to think about. People asked her questions about the case and how she had solved it, but she had replied flatly and without interest. All she wanted to do was collapse on her bed and go to sleep. A train ride of a few hours had felt more like one that had taken a few days.

However, when she finally reached her dormitory, instead of falling on the bed and closing her eyes, she took a parchment and quill from her trunk, sat down on her bed, and began to write a letter. It was no ordinary letter, but one that would tell the entire story.

_Dear Mum and Dad_, it began. _You'd never guess what happened on the way to school today..._

_

* * *

_

**Note**: thanks to everyone who has reviewed or read this story. It's been so much fun to write! There will, eventually, be a sequel to this, but for now, the case is closed. ;-)


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